The descriptive epidemiology of infectious diseases in the elderly is incompletely defined, hence geriatric preventive medical planning is partially empiric. By coordinating the efforts of health professionals in geriatric medicine, infectious diseases, infection control-epidemiology, and computer sciences, the determinants and dynamics of infections in the elderly can be defined. The project aims are to: 1) develop model systems of point prevalence and incidence surveillance mechanisms for infections in elderly care facilities; 2) apply computer technology to collate and analyze multiple factors potentially associated with acquisition of infection (i.e., stratification by age, diseases, procedures, antibiotic use, morbidity/mortality, and related concerns); 3) analyze demographics, risk factors, immunization status, and surveillance methods (periodic prevalence vs daily incidence) in community nursing home versus in-hospital "swing-bed" type settings by multivariate analysis; and 4) plan appropriate infection control policies and procedures for elderly patients in various long-term settings based on risk factors derived from study data. Nurse epidemiologists will conduct daily infection surveillance and monthly prevalence surveys at two facilities (private nursing home and VA-based geriatric care unit). Surveillance data will include demographics of entire facilities and specific patient factors (age, diseases, microbiological results, etc.) recorded on predesigned cards for rapid entry into a computerized system. Results will be collated and reviewed on at least a weekly basis. It will require the use and understanding of routine infection control practices, disease pathogenesis, standards of geriatric care, antibiotic utilization criteria, and statistical methods to critically analyze study results. In addition to project aims stated above, long-term objectives include design of preventive medical protocols based on study data, development of risk indices, analysis of cost-effectiveness of geriatric nurse epidemiologists, impact of immunizations, and use of the model system for training geriatric nurses and physicians concerned with infection control.